1. Field of the Invention
The present invention relates to an apparatus for measuring the vibration characteristic such as resonance characteristic of a head gimbal assembly, the head gimbal assembly being installed in a hard disk drive that is used with an information processor such as a computer.
2. Description of Related Art
A head gimbal assembly includes a head suspension and a slider attached to the head suspension and is driven by a voice coil motor, to move from track to track or follow a track on a hard disk. During the operation, the head gimbal assembly vibrates at high frequencies. It is important, therefore, to find the resonance characteristic of the head gimbal assembly and optimize the resonance characteristic.
There is a need of an apparatus capable of easily measuring the resonance characteristic of a head gimbal assembly.
An apparatus according to a related art for measuring the resonance characteristic of a head gimbal assembly employs a laser Doppler vibrometer to measure the vibration of a head of the head gimbal assembly. To vibrate the head gimbal assembly, the related art uses a shaker, and to measure the vibration of the shaker, the related art employs an accelerometer 103 shown in FIG. 14. The accelerometer 103 is attached to a fixture 101 that is fixed to the shaker. The accelerometer 103 in the fixture 101 limits the size, shape, and material of the fixture 101.
Head gimbal assemblies are being made smaller to reduce the sizes of devices in which the head gimbal assemblies are installed. Due to this, the resonance frequencies of head gimbal assemblies are increasing. In the related art of FIG. 14, the accelerometer 103 included in the fixture 101 limits the resonance frequency of a measuring apparatus employing the fixture 101. As a result, the related art raises a problem that the resonance frequency of a head gimbal assembly to be measured easily harmonizes with that of the measuring apparatus to make it impossible to measure the resonance frequency of the head gimbal assembly.
The above-mentioned related art is disclosed in Japanese Unexamined Patent Application Publication No. 2004-101186.